50" LG Plasma TV issues

[vortalexfan]

Originally Posted by dr.ido

If the power supply is ok it will start up without the main board connected - Obviously without the main connected the LED will not come on.

If the power supply does not start then you either have a bad power supply or one of your sustain boards is shorted and that is causing the power supply to shut down.

Apply power with only AC in connected to the power supply. If it is ok it will start up and you can measure the voltages. If all the voltages are where they should be then your power supply is probably ok.

Connect the power to the sustain boards one at a time and repeat the test.

EXT_AUTO_GEN is correct. Short these points (I just poke a piece of wire in the holes) and the controller will generate various test patterns.

It is the main chip under the heat sink. I remove the heat sink, apply liquid flux around the edges and heat it with the heat gun for a few minutes. Then I let it cool for a while and hook it up again. Success rate so far is 7 out of 10. If they start up I leave them running all day/night. All the ones that were still working the next day went out to customers and didn't come back. Those that failed did so pretty quickly.

That said, there is no point heating the main board if you can't get it to power up and make test patterns.

OK So when the mainboard is disconnected from the power supply does the TV power up on its own without needing to hit the power button? If So then I think the TV is working like it should and it is like you said and is just a matter of needing to reflow the solder on the main chip on the main board because with the mainboard disconnected from power and the TV hooked up to AC Mains the TV makes the sound of powering up (a clicking noise) and it doesn't make the second clicking noise of powering off after a few seconds like it does when the mainboard is attached to the power supply board. the only problem is that I don't have anything small enough to insert into the auto_gen jumper holes to see if it produces a test pattern or not.

So I'm assuming that when the TV powers on without the mainboard in the circuit the screen is supposed to be blank unless you have it do the auto_gen function?

Also what setting did you use on your heatgun to reflow the solder on the main chip on the mainboard, in otherwords what temperature setting did you use? Because I don't want to get it too hot and I don't want it too cool either.